ORTHOMETALATION REACTIONS IN TRIFLUOROACETATE DIRHODIUM(II) COMPOUNDS- MOLECULAR-STRUCTURE OF RH2(O2CCF3)2[C6H4)PPH2]2.(PPH3)2.2(C7H8)

Rh2(O2CCF3)3[(C6H4)PPh2].(HO2CCF3)2 reacts with PPh3 yielding the doub ly metalated compound Rh2(O2CCH3)2-[(C6H4)PPh2]2.(HO2CCF3)2. The react ion proceeds Va a reactive intermediate with an equatorial phosphine, 2-O2CCF3)(mu-O2CCF3)2[(C6H4)PPh2](PPh3).(HO2CCF3), which can also be g enerated in moderate yield under photochemical conditions. The structu re of the PPh3 bis-adduct Rh2(O2CCF3)2[(C6H4)PPh2]2.(PPh3)2.2(C7H8) ha s been determined by X-ray diffraction. M(r)=1663.27, orthorhombic, sp ace group Fdd2, a=41.748(9), b=21.620(5), c=17.375(5) angstrom, V=1568 3 angstrom3, Z=8, D(x)=1.41g cm-3 Mo Kalpha radiation (graphite crysta l monochromator, lambda=0.71073 angstrom), mu(Mo Kalpha)=5.57 cm-1, F( 000)=6800, T=293 K. Final conventional R factor=0.035 for 2789 'observ ed' reflections and 422 variables. The molecule shows crystallographic two-fold axis symmetry through the Rh-Rh bond. One toluene solvent mo lecule slightly disordered is present in the asymmetric unit.